Quantification of T and B Cells using TREC and KREC Markers in Children with ITP with a Chronic and Non-Chronic Course

Sarina Levy Mendelovich ¹ Atar Lev ¹ Shraga Aviner ² Nurit Rosenberg ³ Heim Kaplinsky ⁴ Hagit Miskin ⁵ Nechama Sharon ⁶ Aviya Dvir ³ Gili Kenet ³ Irit Eisen Schushan ⁷ Raz Somech ¹

¹., Pediatric Department A and the Immunology Service, Safra Children’s Hospital, Sheba Medical Center, Tel Hashomer, Israel, affiliated to the Sackler Faculty of Medicine, Tel Aviv University,Israel
²Pediatrics, Department of Pediatrics, Barzilai University Medical Center, Ashkelon
³Laboratory, Amalia Biron Research Institute of Thrombosis and Hemostasis, Chaim Sheba Medical Center, Tel Hashome
⁴Pediatric Hemato-oncology Department, Pediatric Hemato-oncology Department, Safra Children's Hospital, Sheba Medical Center, Tel Hashomer
⁵Hematology, Hematoloy Unit, Shaare Zedek Medical Center, Jerusalem.
⁶Pediatric Hemato-oncology Department, Pediatric Hemato-oncology Department, Laniado Hospital, Netanya
⁷Neonatology, Neonatology Department, , Safra Children’s Hospital, Sheba Medical Center, Tel Hashomer.

Introduction: Immune thrombocytopenia, is an acquired immunological disease characterized by a transient or permanent decline in the number of platelets. Measurement of TREC copies in T cells are a marker for thymus function and new T cells, whereas, measurement of KREC copies are a marker of new B cells. The purpose of this study was to examine the function of the thymus and the production of T and B cells by using a quantitative calculation of the TREC and KREC in ITP patients. We compared the clinical course and these markers between the chronic and non chronic patients.

Material and Methods-Blood samples were collected from 44 with a clinical diagnosis of ITP. Real Time PCR was performed on DNA samples in order to quantify the number of copies of TREC and KREC. Clinical data was collected from medical files and the children were retrospectively divided into two groups: chronic and non-chronic. Comparison was done between the two groups.

Results-24 patients were classified as non chronic and 20 patients as chronic. We did not find a difference regarding levels of TREC copies between the chronic, non-chronic and control groups( p=0.105). Regarding KREC copies we found a statistically significant difference between the group of patients compared to controls (p=0.001).

Discussion-The low levels of TREC could be explained by the fact that the mechanism of ITP is primarily mediated by humoral immunity. This is further supported by the increased level of KREC seen in patients. These results may shed light on the immune mechanism of ITP. In the future this may enable using these markers as diagnostic tools as well as monitoring disease course and response to treatment.

File 1